System and method for compact storage and transmission of position and residual information usable in differential global positioning

• US 5,523,763 A
• Filed: 07/19/1994
• Issued: 06/04/1996
• Est. Priority Date: 07/19/1994
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Loomis, Peter V. W.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/277,322
• Time in Patent Office: 686 Days
• Field of Search: 342/357, 455/12.1
• US Class Current: 342/357.44
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]

Abstract

A system and method for optimizing data transmission and storage of minimal sets of position, time, and residual information required for differential global positioning involving at least two GPS receiving stations, one of which may be stationary and at least one of which is mobile, with increased accuracy and compactness. The method includes sending or storing minimal and enhanced combinations of information. If the indicated values are stored rather than immediately transmitted, they may be retrieved for subsequent combination with values established at another station which may be stationary or mobile. The invention relates particularly to the enablement and performance of compacted storage and transmission of position-oriented and residual information for GPS systems and methods.

Claims

1. A method for producing a compressed differential global positioning data set at a mobile GPS receiving location, comprising:

receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said GPS signals being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites;

generating pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

developing position error indications by a least squares operation for each pseudorange error value;

producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight;

producing a position indication for each position error indication produced, based upon a comparison of said position error indications with said initial estimated position; and

transmitting said position indications produced and one of the residual values produced to a second GPS receiving location.

6. The method of claim 1, further comprising transmitting said position error indications and the initial estimated position to the second GPS receiving location.

7. The method of claim 1, further comprising storing into a selected memory said position error indications, the initial estimated position, and at least one residual value.

2. A method for producing a compressed differential global positioning data set at a mobile GPS receiving location, comprising:

receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said GPS signals being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites;

generating pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

developing position error indications by a least squares operation for each pseudorange error value;

producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight;

producing a position indication for each position error indication produced, based upon a comparison of said position error indications with said initial estimated position; and

storing said position indications produced and one of the residual values produced at said mobile GPS receiving location.

3. A method for producing a compressed differential global positioning data set at a mobile GPS receiving location, comprising

receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said GPS signals being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites;

generating pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

developing position error indications by a least squares operation for each pseudorange error value;

producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight;

producing a position indication for each position error indications produced, based upon a comparison of said position error indications with said initial estimated position; and

making a linear combination of residual values for more compact data transmission and storage.

4. The method of claim 3 further comprising transmitting said linear combination and said position indications to a second GPS receiving location.

5. The method of claim 3 further comprising storing into a selected memory said position indications produced and said linear combination.

8. A position determination system for enabling determination of the position of a mobile GPS receiving station, comprising:

a mobile GPS receiver for receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said mobile GPS receiver being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites based upon GPS signals received from said at least five GPS signal transmitting satellites;

a pseudorange generator for producing pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

means for producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

means for developing position error indications by a least squares operation for each pseudorange error value;

means for producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight;

means for producing a position indication for each position error indication produced, based upon a comparison of said position error indications with said initial estimated position; and

means for transmitting said position indications produced and one of the residual values produced to a second GPS receiving location.

9. The position determination system of claim 8, further comprising means for storing said position indications produced and one of the residual values produced at said mobile GPS receiving location.

10. The position determination system of claim 8, comprising additionally means for making a linear combination of residual values for more compact data transmission and storage.

11. The position determination system of claim 10, comprising means for transmitting said linear combination and said position indications to a second GPS receiving location.

12. The position determination system of claim 10, comprising means for storing into a selected memory said position indications produced and said linear combination.

13. The position determination system of claim 8, further comprising means for transmitting said position error indications, the initial estimated position, and at least one residual value, to a second GPS receiving location.

14. The position determination system of claim 8, further comprising means for storing into a selected memory said position error indications, the initial estimated position, and at least one residual value.

15. A GPS position determination system for determining the position of a mobile GPS receiving station, comprising:

a mobile GPS receiver for receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said mobile GPS receiver being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites based upon GPS signals received from said at least five GPS signal transmitting satellites;

a pseudorange generator for producing pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

means for producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

means for developing position error indications by a least squares operation for each pseudorange error value;

means for producing a position indication for each position error indication produced, based upon a comparison of said position error indications with said initial estimated position;

means for producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight; and

a transmitter for transmitting position and residual indications to a second GPS receiving location.

16. The GPS position determination system according to claim 15, wherein said means for producing a residual value for each of said at least five GPS signal transmitting stations is effective for producing linear combinations of said residual values, and said transmitter is effective for transmitting said linear combinations.

17. A GPS position determination system for determining the position of a mobile GPS receiving station, comprising:

a mobile GPS receiver for receiving GPS signals from at least five GPS signal transmitting satellites at a mobile GPS receiving location, said mobile GPS receiver being effective for producing a line-of-sight for each of said at least five GPS signal transmitting satellites based upon GPS signals received from said at least five GPS signal transmitting satellites;

a pseudorange generator for producing pseudorange values for each of said at least five GPS signal transmitting satellites from corresponding ones of said GPS signals;

means for producing pseudorange error values corresponding to said pseudorange values, based upon an initial estimated position of said mobile GPS receiving location;

means for developing position error indications by a least squares operation for each pseudorange error value;

means for producing a position indication for each position error indication produced, based upon a comparison of said position error indications with said initial estimated position;

means for producing a residual value for each of said at least five GPS signal transmitting satellites, based upon corresponding ones of said pseudorange errors, position error indications, and lines-of-sight; and

a storage system for storing position and residual indications at a selected memory location.

18. The GPS position determination system according to claim 17, wherein said means for producing a residual value for each of said at least five GPS signal transmitting stations is effective for producing linear combinations of said residual values, and said storage system is effective for storing said linear combinations.